Digital Orthoimagery, Northeast Minnesota, Spring 2009, 0.5-m Resolution

This page last updated: 05/29/2015
Metadata created using Minnesota Geographic Metadata Guidelines

Go to Section:
1. Overview
2. Data Quality
3. Data Organization
4. Coordinate System
5. Attributes
6. Distribution - Get Data
7. Metadata Reference

Section 1 Overview
Originator Minnesota Department of Natural Resources (MnDNR), Minnesota Pollution Control Agency (PCA), St. Louis County, U.S. Geological Survey (USGS), and Keystone Aerial Surveys Inc.
Title Digital Orthoimagery, Northeast Minnesota, Spring 2009, 0.5-m Resolution
Abstract This dataset contains 4 Band red, green, blue, infrared (RGBI) digital orthophoto imagery of Cook, Lake, St. Louis and Carlton counties in northern Minnesota.

The orthophotos are 0.5 meter ground sample distance (GSD) and are in UTM Zone 15, NAD83 (meters). The tiling format of the imagery is based on a 3.75' x 3.75' quarter quadrangle with a 150 meter buffer on all four sides. This dataset includes 969 digital orthophoto quarter quadrangles (DOQQs) in GeoTiff format with an associated world file, and this metadata file. The data is available online as a web mapping service (WMS).

All imagery was collected by Keystone Aerial Surveys Inc with a Vexcel UltraCamX camera from an altitude of approximately 24,000 feet. All imagery was processed by Keystone using the camera manufacturer's software, Inpho's photogrammetry suite and Keystone-created software.

Funding for this data was provided by the Minnesota Natural Heritage Fund, the Minnesota Clean Water Legacy Act, The Environmental and Natural Resources Trust Fund, St. Louis County, the Coastal Zone Management Program, and the National Geospatial Intelligence Agency.
Purpose The orthophotos will be used by the Minnesota DNR to update the National Wetland Inventory maps and as a base layer for mapping wetlands and other business needs. Additional funding was provided for this enhanced resolution dataset by the Minnesota Pollution Control Agency, St. Louis County, and the U.S. Geological Survey to support their various business needs. This type of leaf-off photography is a critical component for a variety of land management applications including transportation planning, wetland mapping, urban planning, forest management, soil mapping, and utility siting.
Time Period of Content Date 05/2009
Currentness Reference Month that the photography was flown.
Progress Complete
Maintenance and Update Frequency Irregular
Spatial Extent of Data All of Cook, Lake and St. Louis counties and northern portion of Carlton county, Minnesota
Bounding Coordinates -93.102598
Place Keywords Minnesota, MN, Cook, Lake, St. Louis, Carlton, Northern Minnesota, Arrowhead
Theme Keywords imageryBaseMapsEarthCover, Orthophotography, Digital Orthophotography, Ortho, Orthophotos, Digital Orthorectified Images, Digital Orthophotos, DOQ, DOQQ, Imagery, Images, Aerial Photography, Aerial Photos, Digital Aerial Photography, Air Photo, Color Infrared, Four Band Imagery
Theme Keyword Thesaurus ISO 19115 Topic Category
Access Constraints Unrestricted
Use Constraints Imagery is the property of the State of Minnesota.

MnGeo Redistribution conditions: In obtaining this data from the Minnesota Geospatial Information Office (MnGeo), it is understood that you and/or your organization have the right to use it for any purpose. If you modify it, you are encouraged to apply responsible best practices by documenting those changes in a metadata record. If you transmit or provide the data to another user, it is your responsibility to provide appropriate content, limitation, warranty and liability information as you see fit.
Contact Person Information Steve Kloiber, Wetland Monitoring Coordinator
Minnesota Department of Natural Resources
500 Lafayette Road
St. Paul, MN  55155
Phone: 651-259-5164
Browse Graphic None available
Associated Data Sets Some areas of this project were flown at 30-centimeter resolution; see:

For information on other air photos available for Minnesota, see:

Section 2 Data Quality
Attribute Accuracy NA
Logical Consistency NA
Completeness The dataset is complete to the specifications lain out by MNDNR such that there are no omissions or generalizations that affect the completeness of the dataset.
Horizontal Positional Accuracy The target accuracy standard was the American Society for Photogrammetry and Remote Sensing (ASPRS) standard for 1:12,000 scale maps, 95% of well-defined points fall within 24.5 feet. The vendor's horizontal accuracy test yielded a circular root mean square error (RMSE) of 11.0 feet. An independent horizontal accuracy test was performed by the Minnesota DNR. The result from the independent check yielded an RMSE of 6.6 feet with a 95% confidence interval of 11.5 feet. This corresponds to the ASPRS accuracy standard for 1:6000 scale maps.
Vertical Positional Accuracy NA
Lineage Keystone Aerial Surveys Inc. acquired new vertical, digital black and white, color, and color infrared, photography at an altitude of 24,000 feet, at a photo scale of 1''= 5787 (1:69,444) with a 0.5-meter GSD (ground sample distance) with Vexcel UltraCamX cameras. Flight lines were north-to-south with a 60% forward overlap and a 20% side lap. The 48 flight lines and 3239 exposures were flown in May of 2009.

The UltraCamX camera consists of 13 sensors: 9 panchromatic sensors and 4 color sensors. The color sensors are 4810 x 3140 pixels in size, with one sensor capturing red data, one capturing blue data, one capturing green data, and one capturing near-infrared data (band pass 680-940nm). The 9 pan sensors slightly overlap one to another and are used to produce one large image, 14430 x 9420 pixels in size. The vendor's processing software and current calibration are used to create the final image and pan sharpen the color bands to create the final RGBI image at the above dimensions and a pixel size of 7.2 microns.

The digital acquisition was accompanied by the collection of airborne Global Positioning System (GPS) data and inertial measurement unit (IMU) data, the post processing of which yields a strong exterior orientation (EO) for each photograph and a very accurate center position. A fully analytical Aerotriangulation (AT) of the aerial images was conducted using ground control, GPS and the IMU data to further refine the EO for each image to be used in the orthorectification process. This was accomplished with Inpho Match-AT.

The MNDNR provided the USGS 30-meter digital elevation model (DEM) to Keystone for use in the orthorectification process. These were loaded into visualization software to confirm their accuracy and, where needed, were corrected and/or enhanced using Inpho DTMaster.

Digital Orthophoto Quarter-Quads were developed following the USGS standards for digital orthophotos (DOQs) with the exception of pixel resolution (0.5 meters) and file format (TIFF with world files). USGS header (.hdr) files were not included as a deliverable. Keystone used Inpho OrthoMaster to create orthophotos, Inpho OrthoVista to seam the DOQQs and the Inpho suite, ESRI ArcGIS and Photoshop CS3 to radiometrically balance and seam the DOQQs.

MnGeo used the TIFF files to create the WMS (web mapping service) layer that is available online.

Section 3 Spatial Data Organization (not used in this metadata)

Section 4 Coordinate System
Horizontal Coordinate Scheme Universal Transverse Mercator
UTM Zone Number 15
Horizontal Datum NAD83
Horizontal Units meters
Cell Width 0.3
Cell Height 0.3

Section 5 Attributes
Overview Imagery has 4 Bands with the order of Red, Green, Blue and Near Infrared
Detailed Citation
Table Detail:

Section 6 Distribution
Publisher Minnesota Department of Natural Resources
Publication Date 12/2009
Contact Person Information Nancy Rader, GIS Data Coordinator
Minnesota Geospatial Information Office (MnGeo)
658 Cedar Street
St. Paul, MN  55155
Phone: 651-201-2489
Distributor's Data Set Identifier ne2009_doqq_50cm
Distribution Liability MnGeo's data disclaimer is online:
Ordering Instructions These air photos are very large and thus are not provided online for download. Instead, they are available to view as a web map service (WMS), part of MnGeo's Geospatial Image Service. Click on the link below for more information about the Geospatial Image Service and how to use web map services.
Online Linkage I AGREE to the notice in "Distribution Liability" above. Clicking to agree will either begin the download process, link to a service, or provide more instructions. See "Ordering Instructions" above for details.

Section 7 Metadata Reference
Metadata Date 05/29/2015
Contact Person Information Nancy Rader, GIS Data Coordinator
Minnesota Geospatial Information Office (MnGeo)
658 Cedar Street
St. Paul, MN  55155
Phone: 651-201-2489
Metadata Standard Name Minnesota Geographic Metadata Guidelines
Metadata Standard Version 1.2
Metadata Standard Online Linkage

This page last updated: 05/29/2015
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